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 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://github.com/payara/Payara/blob/main/LICENSE.txt
 * See the License for the specific
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 * file and include the License file at legal/OPEN-SOURCE-LICENSE.txt.
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 * GPL Classpath Exception:
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 * exception as provided by the Payara Foundation in the GPL Version 2 section of the License
 * file that accompanied this code.
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 * If applicable, add the following below the License Header, with the fields
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package fish.payara.microprofile.metrics;

import org.eclipse.microprofile.metrics.Metadata;
import org.eclipse.microprofile.metrics.MetricUnits;

/**
 * Utilities around {@link MetricUnits}.
 *
 * @author Jan Bernitt
 */
public final class MetricUnitsUtils {

    private MetricUnitsUtils() {
        throw new UnsupportedOperationException("util");
    }

    public static String baseUnit(String unit) {
        switch (unit) {
        case MetricUnits.BITS:
        case MetricUnits.KILOBITS:
        case MetricUnits.MEGABITS:
        case MetricUnits.GIGABITS:
        case MetricUnits.KIBIBITS:
        case MetricUnits.MEBIBITS:
        case MetricUnits.GIBIBITS:
        case MetricUnits.BYTES:
        case MetricUnits.KILOBYTES:
        case MetricUnits.MEGABYTES:
        case MetricUnits.GIGABYTES:
            return MetricUnits.BYTES;
        case MetricUnits.NANOSECONDS:
        case MetricUnits.MICROSECONDS:
        case MetricUnits.MILLISECONDS:
        case MetricUnits.SECONDS:
        case MetricUnits.MINUTES:
        case MetricUnits.HOURS:
        case MetricUnits.DAYS:
            return MetricUnits.SECONDS;
        default:
            return unit;
        }
    }

    public static Number scaleToBaseUnit(Number value, Metadata metadata) {
        if (!metadata.unit().isPresent()) {
            return value;
        }
        String unit = metadata.getUnit();
        return scaleToBaseUnit(value, unit);
    }

    public static Number scaleToBaseUnit(Number value, String unit) {
        if (unit == null || unit.isEmpty() || unit.equals(MetricUnits.NONE)) {
            return value;
        }
        switch (unit) {
        // bytes from bits
        case MetricUnits.BITS: return value.longValue() / 8d;
        case MetricUnits.KILOBITS: return value.doubleValue() * 1000d / 8d;
        case MetricUnits.MEGABITS: return value.doubleValue() * 1000d * 1000d / 8d;
        case MetricUnits.GIGABITS: return value.doubleValue() * 1000d * 1000d * 1000d / 8d;
        case MetricUnits.MEBIBITS: return value.doubleValue() * 1024d * 1024d / 8d;
        case MetricUnits.GIBIBITS: return value.doubleValue() * 1024d * 1024d * 1024d / 8d;

        // bytes from bytes
        case MetricUnits.BYTES: return value;
        case MetricUnits.KILOBYTES: return value.doubleValue() * 1000d;
        case MetricUnits.MEGABYTES: return value.doubleValue() * 1000d * 1000d;

        // seconds from time unit
        case MetricUnits.NANOSECONDS: return value.longValue()  / 1000d / 1000d / 1000d;
        case MetricUnits.MICROSECONDS: return value.longValue() / 1000d / 1000d;
        case MetricUnits.MILLISECONDS: return value.longValue() / 1000d;
        case MetricUnits.SECONDS: return value;
        case MetricUnits.MINUTES: return value.doubleValue() * 60d;
        case MetricUnits.HOURS: return value.doubleValue() * 60d * 60d;
        case MetricUnits.DAYS: return value.doubleValue() * 60d * 60d * 24d;

        // others
        case MetricUnits.KIBIBITS:
        case MetricUnits.GIGABYTES:
        case MetricUnits.PERCENT:
        case MetricUnits.PER_SECOND:
        default:
            return value;
        }
    }

}
